放牧强度对夏季高寒草甸生物量和植被结构的影响

讨论了放牧强度对高寒草甸夏季草地上生物量和植被结构的影响。结果表明 :轻牧组、中牧组及重牧组各放牧强度对草地优良牧草所占比例影响较大 ,其中 :禾本科牧草分别提高 2 0 .5 %、6.5 % ,减少1 3.5 % ;莎草科牧草分别提高 2 0 .3%、1 0 .4% ,减少 7.7% ;杂类草分别减少 2 0 .5 %、6.5 % ,提高 1 3.5 %。再从草地盖度看 ,优良牧草 (禾草 +莎草 )在轻牧组提高 1 .4% ,中牧和重牧组分别减少 2 .2 %和 6.4% ;杂类草盖度在轻牧和中牧组分别减少 2 1 .3%和 7.2 % ,而在重牧组则提高 3.2 %。

EFFECT OF GRAZING INTENSITY ON BIO- MASS ABOVE GROUND AND VEGETATION STRUCTURE IN SUMMER ALPINE MEADOW

Effect of grazing intensity on biomass and vegetation structure in summer alpine meadow has been discussed in the paper. Ratio of favorable forage has been impacted remarkably by intensity of grazing, the ratio of Gramineae forage increased by 20.5%, 6.5%, 13.5%in treatments of light-grazing, medium-grazing and heavy-grazing respectively; ratio of Cyperaceae forage increased by 20.3%, 10.4%in light and medium treatment and decreased by 7.7% in heavy grazing treatment; forbs decreased by 20.5%, 6.5% inlight and medium grazing treatment, increased by 13.5% in heavy-grazing treatment. Vegetation coverage of Gramineae and Cyoeraceae increased by 1.4% in light-grazing treatment and decreased by 2.2% and 6.4% in medium-grazing and heavy-grazing treatment respectively. Vegetation coverage of forbs decreased by 21.3% and 7.2% in light and medium grazing treatment and increased by 13.2% in heavy grazing treatment.